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Ultraviolet Light (ultraviolet + light)
Terms modified by Ultraviolet Light Selected AbstractsLipids and skin barrier function , a clinical perspectiveCONTACT DERMATITIS, Issue 5 2008Jakob Mutanu Jungersted The stratum corneum (SC) protects us from dehydration and external dangers. Much is known about the morphology of the SC and penetration of drugs through it, but the data are mainly derived from in vitro and animal experiments. In contrast, only a few studies have the human SC lipids as their focus and in particular, the role of barrier function in the pathogenesis of skin disease and its subsequent treatment protocols. The 3 major lipids in the SC of importance are ceramides, free fatty acids, and cholesterol. Human studies comparing levels of the major SC lipids in patients with atopic dermatitis and healthy controls have suggested a possible role for ceramide 1 and to some extent ceramide 3 in the pathogenesis of the disease. Therapies used in diseases involving barrier disruption have been sparely investigated from a lipid perspective. It has been suggested that ultraviolet light as a treatment increases the amount of all 3 major SC lipids, while topical glucocorticoids may lead to a decrease. Such effects may influence the clinical outcome of treatment in diseases with impaired barrier function. We have, therefore, conducted a review of the literature on SC lipids from a clinical perspective. It may be concluded that the number of human studies is very limited, and in the perspective of how important diseases of impaired barrier function are in dermatology, further research is needed. [source] Photodynamic Therapy for the Treatment of Cutaneous Neoplasia, Inflammatory Disorders, and PhotoagingDERMATOLOGIC SURGERY, Issue 5 2009EMILY TIERNEY MD BACKGROUND Photodynamic therapy (PDT) has demonstrated high efficacy, minimal side effects, and improved cosmetic outcome when used for the treatment of actinic keratoses (AK), basal cell carcinoma (BCC), squamous cell carcinoma, and photoaging. METHODS To review the literature on the use of PDT in dermatologic surgery using MEDLINE. RESULTS Published clinical studies using PDT in the treatment of AKs yield overall efficacy rates ranging from 50% to 71% with one treatment to as high as 88% to 90% with two or more treatments. For superficial BCC, initial clearance rates were 76% to 97%, and for Bowen's disease, initial clearance rates ranged from 72% to 94% overall. The use of PDT for photorejuvenation is a relatively new application of this technology, which has shown promise in improving the appearance of fine lines, pigmentary variation, and telangiectasias. CONCLUSIONS The advantages of photodynamic therapy include the capacity for noninvasive targeted therapy through topical application of aminolevulinic acid and methyl aminolevulinic acid, with outstanding cosmetic results. Although the theory behind the use of chemical photosensitizers and ultraviolet light to treat a wide variety of skin disorders is straightforward, the practical application of this technology is evolving. Additional research into the precise mechanisms of action for specific photosensitizers and optimal light sources will be highly beneficial to the advancement of this technology. [source] Visualizing neurons one-by-one in vivo: Optical dissection and reconstruction of neural networks with reversible fluorescent proteinsDEVELOPMENTAL DYNAMICS, Issue 8 2006Shinsuke Aramaki Abstract A great many axons and dendrites intermingle to fasciculate, creating synapses as well as glomeruli. During live imaging in particular, it is often impossible to distinguish between individual neurons when they are contiguous spatially and labeled in the same fluorescent color. In an attempt to solve this problem, we have taken advantage of Dronpa, a green fluorescent protein whose fluorescence can be erased with strong blue light, and reversibly highlighted with violet or ultraviolet light. We first visualized a neural network with fluorescent Dronpa using the Gal4-UAS system. During the time-lapse imaging of axonal navigation, we erased the Dronpa fluorescence entirely; re-highlighted it in a single neuron anterogradely from the soma or retrogradely from the axon; then repeated this procedure for other single neurons. After collecting images of several individual neurons, we then recombined them in multiple pseudo-colors to reconstruct the network. We have also successfully re-highlighted Dronpa using two-photon excitation microscopy to label individual cells located inside of tissues and were able to demonstrate visualization of a Mauthner neuron extending an axon. These "optical dissection" techniques have the potential to be automated in the future and may provide an effective means to identify gene function in morphogenesis and network formation at the single cell level. Developmental Dynamics 235:2192,2199, 2006. © 2006 Wiley-Liss, Inc. [source] Complete sequence of the IncP-9 TOL plasmid pWW0 from Pseudomonas putidaENVIRONMENTAL MICROBIOLOGY, Issue 12 2002Alicia Greated Summary The TOL plasmid pWW0 (117 kb) is the best studied catabolic plasmid and the archetype of the IncP-9 plasmid incompatibility group from Pseudomonas. It carries the degradative (xyl) genes for toluenes and xylenes within catabolic transposons Tn4651 and Tn4653. Analysis of the complete pWW0 nucleotide sequence revealed 148 putative open reading frames. Of these, 77 showed similarity to published sequences in the available databases predicting functions for: plasmid replication, stable maintenance and transfer; phenotypic determinants; gene regulation and expression; and transposition. All identifiable transposition functions lay within the boundaries of the 70 kb transposon Tn4653, leaving a 46 kb sector containing all the IncP-9 core functions. The replicon and stable inheritance region was very similar to the mini-replicon from IncP-9 antibiotic resistance plasmid pM3, with their Rep proteins forming a novel group of initiation proteins. pWW0 transfer functions exist as two blocks encoding putative DNA processing and mating pair formation genes, with organizational and sequence similarity to IncW plasmids. In addition to the known Tn4651 and IS1246 elements, two additional transposable elements were identified as well as several putative transposition functions, which are probably genetic remnants from previous transposition events. Genes likely to be responsible for known resistance to ultraviolet light and free radicals were identified. Other putative phenotypic functions identified included resistance to mercury and other metal ions, as well as to quaternary ammonium compounds. The complexity and size of pWW0 is largely the result of the mosaic organization of the transposable elements that it carries, rather than the backbone functions of IncP-9 plasmids. [source] Importance of maternal transfer of the photoreactive polycyclic aromatic hydrocarbon fluoranthene from benthic adult bivalves to their pelagic larvaeENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2000Marguerite C. Pelletier Abstract Laboratory experiments were conducted to determine if maternal transfer of polycyclicaromatichydrocarbons (P AH) from benthic adult bivalves could result in phototoxicity to their pelagic larvae when exposed to ultraviolet light (UV). In these experiments, adult bivalves were exposed to water or sediments amended with the model photoreactive PAH, fluoranthene. Elevated adult fluoranthene tissue concentrations were correlated with embryo concentrations. Embryonic mortality was enhanced by exposure to ultraviolet light when adult tissue fluoranthene levels were greater than 5,000 ,g/g lipid. While the exposure concentrations used in this experimental system were high, ultraviolet light exposure levels were low. Also, some of the PAHs are more potent than the model compound used in this study. These results indicate that maternal transfer of photoactive PAHs from organisms living in contaminated sediments may represent a significant adverse effect to populations of benthic bivalves. [source] Effects of Ultraviolet Radiation on Locomotion and Orientation in Roughskin Newts (Taricha granulosa)ETHOLOGY, Issue 3 2000Andrew R. Blaustein Environmental changes, including those associated with the atmosphere may significantly affect individual animals and ultimately populations. Ultraviolet (UV) radiation, perhaps increasing due to stratospheric ozone depletion, has been linked to mortality in a number of organisms, including amphibians. The eggs and larvae of certain amphibian species hatch at significantly lower rates when exposed to ambient ultraviolet light. Yet little is known about the sublethal effects of UV radiation. For example, UV radiation may affect specific behaviors of an animal that could alter its ability to survive. To examine if UV radiation affects amphibian behavior, we used roughskin newts (Taricha granulosa) as a model. Newts were exposed to low-level doses of UV in the laboratory and then tested in the field to examine if UV-exposed and control (no UV) newts differed in orientation towards water or in locomotor activity levels. UV-exposed and control newts both exhibited a significant orientation towards water in field tests but there was no significant difference in orientation between treatments. However, UV-exposed newts were significantly more active than control newts. Our results suggest that exposure to short-term low levels of UV radiation alters certain behaviors. Environmentally induced changes in behavior may have significant ecological and evolutionary consequences. [source] Mast cells and their role in the neuro-immune-endocrine axisEXPERIMENTAL DERMATOLOGY, Issue 9 2004J. Bienenstock It has become clear that the immune and nervous systems communicate constantly to maintain homeostasis and a coordinated and continuing adaptive response to an ever-changing environment. Evidence from mast cell nerve communication, as an example of this interaction, has been obtained in a variety of tissues and circumstances, most especially in the intestine and skin. Bidirectional communication has been shown in vivo, ex vivo, in vitro and in coculture experiments involving the two cell types. Examples will be given of these various situations and involve normal physiological situations and those involved in response to infection and inflammation as well as in response to ultraviolet light. More recent examples of the importance of mast cells in the regulation of central nervous activity including the secretion of hormones by the pituitary gland, and thereby the regulation of the HPA axis as well as involvement in behavioural change will be addressed. Through its potential communication with the nervous system, the mast cell can be regarded as a sentinel cell or receptor, especially located at surfaces exposed to the environment, which specifically and non-specifically react to molecules and substances, foreign to the organism, so as to help orchestrate the complex and integrated responses required to maintain homeostasis. [source] Altered kelp (Laminariales) phlorotannins and growth under elevated carbon dioxide and ultraviolet-B treatments can influence associated intertidal food websGLOBAL CHANGE BIOLOGY, Issue 8 2007ANDREW K. SWANSON Abstract Due to the importance of brown algae, such as kelp (Laminariales, Phaeophyta), within most cool nearshore environments, any direct responses of kelp to multiple global changes could alter the integrity of future coastal marine systems. Fifty-five-day manipulation of carbon dioxide (CO2) and ultraviolet light (UVB) within outdoor sea-tanks, approximating past, present and two predicted future levels, examined the direct influences on Saccharina latissima (=Laminaria saccharina) and Nereocystis luetkeana development and biochemistry, as well as the indirect influences on a marine herbivore (Tegula funebralis; Gastropoda, Mollusca) and on naturally occurring intertidal detritivores. Kelp species displayed variable directional (negative and positive growth) and scale responses to CO2 and UVB manipulations, which was influenced by interactions. Kelp phlorotannin (phenolic) production in blade tissues was induced by elevated UVB levels, and especially enhanced (additively) by elevated CO2, further suggesting that some actively growing kelp species are carbon limited in typical nearshore environments. Negative indirect effects upon detritivore consumers fed CO2 -manipulated kelp blade tissues were detected, however, no statistical relationships existed among UVB-treated tissues, and test herbivores did not distinguish between phlorotannin-altered CO2: UVB-treated kelp blade tissues. Results suggest that past and future conditions differentially benefit these kelp species, which implies a potential for shifts in species abundance and community composition. Higher CO2 conditions can indirectly impede marine decay processes delaying access to recycled trace nutrients, which may be disruptive to the seasonal regrowth of algae and/or higher trophic levels of nearshore ecosystems. [source] Nanoparticle Coating for Advanced Optical, Mechanical and Rheological Properties,ADVANCED FUNCTIONAL MATERIALS, Issue 16 2007F. Hakim Abstract Primary titania nanoparticles were coated with ultrathin alumina films using Atomic Layer Deposition (ALD). The deposited films were highly uniform and conformal with an average growth rate of 0.2,nm per coating cycle. The alumina films eliminated the surface photocatalytic activity of titania nanoparticles, while maintained their original extinction efficiency of ultraviolet light. Deposited films provided a physical barrier that effectively prevented the titania surface from oxidizing organic material whereas conserving its bulk optical properties. Parts fabricated from coated powders by pressureless sintering had a 13,% increase in surface hardness over parts similarly fabricated from uncoated particles. Owing to its homogeneous distribution, the secondary alumina phase suppressed excessive grain growth. Alumina films completely reacted during sintering to form aluminum titanate composites, as verified by XRD. Coated particles showed a pseudoplastic behavior at low shear rates due to modified colloidal forces. This behavior became similar to the Newtonian flow of uncoated nanoparticle slurries as the shear rate increased. Suspensions of coated particles also showed a decreased viscosity relative to the viscosity of uncoated particle suspensions. [source] Mutation rate of MAP2K4/MKK4 in breast carcinoma ,,HUMAN MUTATION, Issue 1 2002Gloria H. Su Abstract The stress-activated protein kinase (SAPK) pathways represent phosphorylation cascades that convey pro-apoptotic signals. The relevant inputs include Ras proteins as well as exposure of cells to ultraviolet light, tumor-necrosis factor, and other stress-related inputs. The mitogen-activated protein kinase kinase (MAPKK) homolog MAP2K4 (MKK4, SEK, JNKK1) is a centrally-placed mediator of the SAPK pathways. MAP2K4 mutations or homozygous deletions are reported in about 5% of a wide variety of tumor types. The exception is breast cancer, where genetic inactivation in 3 of 22 (15%) cell lines had suggested that the mutational involvement of MAP2K4 might be accentuated in this tumor type. This finding might have represented an important difference, or solely a chance numerical variation. To address this question, we studied an independent panel of 20 breast cancer cell lines and xenografts for MAP2K4 alterations. We found a splice acceptor mutation accompanied by loss of the other allele in the cell line MPE600. This was the sole alteration in this panel (5% of tumors). These data seem to re-establish a rather consistent rate of genetic inactivation of MAP2K4 among most tumor types, including breast cancer. The genetic evaluation of other mediators of the SAPK pathways might offer insight into a promising, but as yet poorly defined, tumor-suppressive system. © 2001 Wiley-Liss, Inc. [source] The mosquito ribonucleotide reductase R2 gene: ultraviolet light induces expression of a novel R2 variant with an internal amino acid deletionINSECT MOLECULAR BIOLOGY, Issue 3 2004G. Jayachandran Abstract Using RT-PCR, we examined expression of the ribonucleotide reductase R2 subunit (RNR-R2) in Aedes albopictus mosquito cells after treatment with ultraviolet light (UV). In control cells, a predominant band at 1.2 kb corresponded to the full-length cDNA. A smaller 650 bp band was unique to UV-treated cells. Sequence analysis showed that the 650 bp band encoded a protein with an internal deletion of 179 amino acids, relative to Ae. albopictus RNR-R2. The N-terminal twenty amino acids were identical between AalRNR-R2 and Aal,R2; downstream of the deletion, the proteins differed at only four residues. In Aal,R2, the internal deletion spanned five residues critical to RNR-R2 enzymatic activity, including a key tyrosine residue that generates an essential free radical. The full-length 46 kDa and truncated 25 kDa RNR-R2 proteins were shown to be expressed on Western blots, and to differ in their subcellular localization. Similarly, expression of the two proteins was differentially regulated during the cell cycle, and expression of Aal,R2 predominated after UV treatment. Aal,R2 resembled a human RNR-R2 variant called p53R2, which was induced by agents that damage DNA. As was the case with p53R2 and its antisense RNA, levels of Aal,R2 were diminished after treatment of mosquito cells with RNAi corresponding to p53 from Drosophila melanogaster. Examination of the AalRNR-R2 homologue in the Anopheles gambiae genome suggested that Aal,R2 resulted from precise splicing between Exons 1, 4 and 5, eliminating Exons 2 and 3. The likelihood that Aal,R2 is a non-enzymatic, functional participant in DNA metabolism is suggested by enhancement of DNA repair in an in vitro system and by the presence of a similar gene (rnr4) in yeast. [source] Intrinsic and extrinsic factors in skin ageing: a reviewINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 2 2008M. A. Farage Synopsis As the proportion of the ageing population in industrialized countries continues to increase, the dermatological concerns of the aged grow in medical importance. Intrinsic structural changes occur as a natural consequence of ageing and are genetically determined. The rate of ageing is significantly different among different populations, as well as among different anatomical sites even within a single individual. The intrinsic rate of skin ageing in any individual can also be dramatically influenced by personal and environmental factors, particularly the amount of exposure to ultraviolet light. Photodamage, which considerably accelerates the visible ageing of skin, also greatly increases the risk of cutaneous neoplasms. As the population ages, dermatological focus must shift from ameliorating the cosmetic consequences of skin ageing to decreasing the genuine morbidity associated with problems of the ageing skin. A better understanding of both the intrinsic and extrinsic influences on the ageing of the skin, as well as distinguishing the retractable aspects of cutaneous ageing (primarily hormonal and lifestyle influences) from the irretractable (primarily intrinsic ageing), is crucial to this endeavour. Résumé Comme le pourcentage de la population vieillissante dans les pays industrialisés s'accroît, les préoccupations dermatologiques des personnes âgées augmentent en importance sur le plan médical. Les modifications structurelles intrinsèques sont une conséquence naturelle du vieillissement et sont génétiquement déterminées. La vitesse de vieillissement diffère significativement selon les différentes populations et selon les différents sites anatomiques, même pour un seul individu. La vitesse intrinsèque du vieillissement de la peau pour un individu peut être aussi très influencée par les facteurs personnels et environnementaux, en particulier le taux d'exposition à la lumière ultra-violette. La photodégradation qui accélère considérablement le vieillissement visible de la peau augmente également beaucoup le risque de formation de néoplasme cutané. Au fur et à mesure que la population vieillit, il faut davantage se préoccuper de diminuer la morbidité réelle associée au vieillissement de la peau, plutôt que de palier à ses conséquences cosmétiques. Il est donc crucial de s'efforcer à mieux comprendre les facteurs intrinsèques et extrinsèques qui agissent sur le vieillissement de la peau et aussi de faire la distinction entre les aspects réversibles du vieillissement cutané (facteurs essentiellement hormonaux et mode de vie) et les aspects irréversibles (principalement le vieillissement intrinsèque). [source] Hypoxia and oxidation levels of DNA and lipids in humans and animal experimental modelsIUBMB LIFE, Issue 11 2008Peter Møller Abstract The objective of this review was to evaluate the association between hypoxia and oxidative damage to DNA and lipids. Evaluation criteria encompassed specificity and validation status of the biomarkers, study design, strength of the association, dose-response relationship, biological plausibility, analogous exposures, and effect modification by intervention. The collective interpretation indicates persuasive evidence from the studies in humans for an association between hypoxia and elevated levels of oxidative damage to DNA and lipids. The levels of oxidatively generated DNA lesions and lipid peroxidation products depend on both the duration and severity of the exposure to hypoxia. Largest effects are observed with exposure to hypoxia at high altitude, but other factors, including ultraviolet light, exercise, exertion, and low intake of antioxidants, might contribute to the effect observed in subjects at high altitude. Most of the animal experimental models should be interpreted with caution because the assays for assessment of lipid peroxidation products have suboptimal validity. © 2008 IUBMB IUBMB Life, 60(11): 707,723, 2008 [source] Enhanced photodegradation efficiency of polyethylene-TiO2 nanocomposite film with oxidized polyethylene waxJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2010Wenjun Fa Abstract A novel photodegradable polyethylene-oxidized polyethylene wax-TiO2 (PE-OPW-TiO2) nanocomposite film was prepared by embedding the organically modified TiO2 nanoparticles into commercial PE in the presence of OPW. The photocatalytic degradation behavior under ultraviolet light or solar light was investigated by examining the weight loss of the composite films, UV,vis transmittance spectrum, scanning electron microscope (SEM), and gel permeation chromatogram (GPC). The results show that OPW, as a dispersant and a compatibiliser, markedly improves the dispersion and compatibility of TiO2 nanoparticles in PE resins. The PE-OPW-TiO2 composite film demonstrates much higher photodegradation efficiency and much better mechanical property than either the PE-TiO2 composite film or the pure PE film. The weight-average molecular weight (Mw) of the PE-OPW-TiO2 composite film decreased 94.3% and the number-average molecular weight (Mn) decreased 84.5% after 38 days solar light irradiation. The photocatalytic degradation mechanism of the film is briefly discussed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Behavioural evidence for ultraviolet vision in a tetraonid species , foraging experiment with black grouse Tetrao tetrixJOURNAL OF AVIAN BIOLOGY, Issue 2 2002Heli Siitari In addition to wavelengths visible to humans (400,700 nm), many birds are able to detect near ultraviolet light (320,400 nm). Most studies of ultraviolet (UV) vision in birds have concentrated on the importance of UV vision in intraspecific signalling, especially in passerine birds. However, birds may also use UV vision for other purposes, e.g. foraging. We performed a laboratory experiment to test whether a tetraonid species, black grouse Tetrao tetrix, could detect the difference between UV-reflecting and non-UV-reflecting food items (two colour morphs of bilberry Vaccinium myrtillus). Black grouse preferred UV-reflecting berries when UV light was used for illumination, but showed no preference in the absence of UV light. This observation establishes a potential UV sensitivity in this species; such a sensitivity should be considered in behavioural experiments with this species. [source] MMP-2, TIMP-2 and MT1-MMP are differentially expressed in lesional skin of melanocytic nevi and their expression is modulated by UVB-lightJOURNAL OF CUTANEOUS PATHOLOGY, Issue 7 2002S. Krengel Background:, In malignant melanoma, recent studies have demonstrated an important role of matrix-metalloproteinase 2 (MMP-2), its co-activating enzyme membrane-type matrix-metalloproteinase 1 (MT1-MMP), and the endogenous inhibitor of MMP-2, tissue-inhibitor of matrix metalloproteinase 2 (TIMP-2). Melanocytic nevi are benign neoplasms of the melanocytic lineage, but may exhibit dysplastic features that can be difficult to distinguish from early stage melanoma. As shown in earlier studies, nevi show important morphological and phenotypical changes in response to ultraviolet light (UVB) irradiation. Objective:, To clarify the role of MMP-2, TIMP-2 and MT1-MMP in UVB-irradiated vs. non-irradiated melanocytic nevi. Methods:, Immunohistochemical comparison of the MMP-2, TIMP-2 and MT1-MMP expression pattern. Results:, MMP-2 is expressed by lesional keratinocytes and its expression is up-regulated by UVB-irradiation. MMP-2 expression was not observed in melanocytic cells. TIMP-2, by contrast, is predominantly expressed by melanocytic nevus cells, and its expression is in part down-regulated by UVB-irradiation. MT1-MMP is expressed by basal keratinocytes and to a weaker extent by melanocytic nevus cells. Conclusions:, MMP-2 expression by keratinocytes in nevi probably represents the result of activation of keratinocyte turnover in lesional epidermis. MMP-2 could play a role in the downward movement of junctional nevus cells into the dermis. The reduction of TIMP-2 expression in melanocytic cells by UV-light together with the enhanced expression of MMP-2 in the adjacent epidermis may promote basement membrane degradation. The expression pattern of MT1-MMP in close proximity to epithelial,mesenchymal interfaces underlines the synergistic role of MT1-MMP in this process. [source] Skin-derived fibroblasts from long-lived species are resistant to some, but not all, lethal stresses and to the mitochondrial inhibitor rotenoneAGING CELL, Issue 1 2007James M. Harper Summary Fibroblast cell lines were developed from skin biopsies of eight species of wild-trapped rodents, one species of bat, and a group of genetically heterogeneous laboratory mice. Each cell line was tested in vitro for their resistance to six varieties of lethal stress, as well as for resistance to the nonlethal metabolic effects of the mitochondrial inhibitor rotenone and of culture at very low glucose levels. Standard linear regression of species-specific lifespan against each species mean stress resistance showed that longevity was associated with resistance to death induced by cadmium and hydrogen peroxide, as well as with resistance to rotenone inhibition. A multilevel regression method supported these associations, and suggested a similar association for resistance to heat stress. Regressions for resistance to cadmium, peroxide, heat, and rotenone remained significant after various statistical adjustments for body weight. In contrast, cells from longer-lived species did not show significantly greater resistance to ultraviolet light, paraquat, or the DNA alkylating agent methylmethanesulfonate. There was a strong correlation between species longevity and resistance to the metabolic effects of low-glucose medium among the rodent cell lines, but this test did not distinguish mice and rats from the much longer-lived little brown bat. These results are consistent with the idea that evolution of long-lived species may require development of cellular resistance to several forms of lethal injury, and provide justification for evaluation of similar properties in a much wider range of mammals and bird species. [source] Microbial Reduction Efficiencies of Filtration, Electrostatic Polarization, and UV Components of a Germicidal Air Cleaning SystemJOURNAL OF FOOD SCIENCE, Issue 6 2002C.J. Cundith ABSTRACT: This study determined the effectiveness of components of a germicidal air-cleaning system involving filtration, electrostatic polarization, and UV light on the reduction of airborne bacteria and molds. The filter alone, filter and electrostatic polarization combined, and the filter, electrostatic polarization, and UV light were found to be effective (P < 0.05) in reducing a given concentration of M. luteus and S. marcescens by 90 to 92%. The same components were also found to be effective (P < 0.05) in reducing indigenous airborne bacteria and molds from ambient air in processing plant production conditions by 62 to 77% after only 1 pass through the filtration system. A germicidal air-filtration system utilizing electrostatic polarization and ultraviolet light can be used to reduce the chance of contaminating surfaces with airborne bacteria and molds. [source] A Novel Mitogen-Activated Protein Kinase Gene in Maize (Zea mays), ZmMPK3, is Involved in Response to Diverse Environmental CuesJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 5 2010Jinxiang Wang In search for components of mitogen-activated protein kinase (MAPK) cascades in maize (Zea mays) involved in response to abscisic acid (ABA) stimulus, a novel MAPK gene, ZmMPK3, from ABA-treated maize leaves cDNA was isolated and characterized. The full length of the ZmMPK3 gene is 1 520 bp and encodes a 376 amino acid protein with a predicted molecular mass of 43.5 kD and a pI of 5.83. ZmMPK3 contains all 11 MAPK conserved subdomains and the phosphorylation motif TEY. Amino acid sequence alignment revealed that ZmMPK3 shared high identity with group-A MAPK in plants. A time course (30,360 min) experiment using a variety of signal molecules and stresses revealed that the transcripts level of ZmMPK3 accumulated markedly and rapidly when maize seedlings were subjected to exogenous signaling molecules: ABA, H2O2, jasmonic acid and salicylic acid, various abiotic stimuli such as cold, drought, ultraviolet light, salinity, heavy metal and mechanical wounding. Its transcription was also found to be tissue-specific regulated. Here, we show that ABA and H2O2 induced a significant increase in the ZmMPK3 activity using immunoprecipitation and in-gel kinase assay. Furthermore, the results showed that the ZmMPK3 protein is localized mainly to the nucleus. These results suggest that the ZmMPK3 may play an important role in response to environmental stresses. [source] Effects of melatonin on paraquat or ultraviolet light exposure-induced DNA damageJOURNAL OF PINEAL RESEARCH, Issue 4 2001Hiro-aki Yamamoto The effect of paraquat or ultraviolet (UV) light exposure on calf thymus DNA was investigated in vitro. When paraquat (0.1, 0.25, 0.5, or 1.0 mM) was incubated with brain or lung homogenates prepared from mice in the presence of calf thymus DNA at 37°C for 90 min, paraquat inflicted damage to DNA in a concentration-dependent manner. However, DNA damage was completely abolished by co-treatment with melatonin (1.5 mM), a hydroxyl radical (,OH) scavenger. In addition, when paraquat (1.0 or 2.5 mM) was incubated with liver microsomes in the presence of calf thymus DNA and Fe3+ (3.0 ,M) at 37°C for 90 min, DNA damage also occurred and was prevented by the co-treatment of melatonin (1.5 mM). DNA was also damaged by UV light exposure or when the Fenton reaction was induced; the Fenton reaction generates ,OH; again, the damage was blocked by the co-treatment of melatonin. These results suggest that ,OH induced by paraquat or UV light probably account for the DNA damage. In short, DNA damage induced by paraquat and UV radiation were completely prevented by co-treatment with the ,OH scavenger, melatonin. [source] Synthesis and characterization of a bis-(4-trifluoromethanesulfonyloxyphenyl)phenylamine monomer and its polymer for light-emitting applicationsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 10 2007Huseyin Zengin Abstract This study focuses on the preparation, polymerization, characterization, and optical properties of a new bis-(4-trifluoromethanesulfonyloxyphenyl)phenylamine monomer. This is the first nitrogen-containing monomer having nitrogen atoms as bridges between phenyl rings, and it was synthesized in three steps. The polymerization was carried out through the Ni(0)-catalyzed homocoupling reaction of the bis-(4-trifluoromethanesulfonyloxyphenyl)phenylamine compound. The resulting polymer, polybis(paraphenyl)phenylamine, emitted an intense blue color (where , = 415 nm) upon irradiation by ultraviolet light. The photoluminescence quantum yield was found to be 36% with a long excited-state lifetime of 3.3 ns. Electrical conductivity data for an HCl-doped film of the polymer were also examined. This novel polymer is of interest as an organic emitting material for electroluminescent devices. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1860,1867, 2007 [source] Characterization of parylene-N and parylene-C photooxidationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 10 2003K. G. Pruden Abstract Parylene-N and parylene-C are polymers of interest for microelectronic and medical coating applications. Modifications for improved surface properties could make them even more useful in such applications. Parylene-N and parylene-C films were exposed to ultraviolet light in the presence of oxygen and analyzed with Rutherford backscattering spectrometry, secondary-ion mass spectroscopy, X-ray photoelectron spectroscopy, and infrared spectroscopy. This study shows that such exposure results in the formation of aldehyde and carboxylic acid groups near the surface of the films. At the maximum exposure dose, the concentration of oxygen in both parylene-N and parylene-C is about 13% at the film surface, and it decreases exponentially with increasing depth. Further modeling and optimization of this process would allow it to be used to tailor the surface concentration of oxygenated species in parylene for the optimization of adhesion and wettability or for the chemical binding of other moieties. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1486,1496, 2003 [source] A Facile Route to Synthesize the Ti5NbO14 Nanosheets by Mechanical Cleavage ProcessJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2 2010Na Zhang Layered and rod-like K3Ti5NbO14 was synthesized via the solid-state chemistry, and it was exfoliated into nanosheets through a novel mechanical cleavage technology. X-ray diffraction was utilized to determine the phase changes of all the specimen during the total process, and the microstructure of the samples was analyzed by scanning electron microscope and transmission electron microscope. The formation mechanism was also discussed in detail, the results indicated that the compression and shearing should play a main function in the crack and the cleavage of the aggregated layered compound. UV,vis absorption spectroscopy was used to monitor the consecutive buildup of the (PEI/Ti5NbO14)n film. The resulting quasi-linear increase at the top absorbance as a function of the sequential assembly number for the multilayer film indicated that the nanosheet had deposited uniformly in each dipping cycle. The photocatalytic activity of K3Ti5NbO14 -related products was examined. Compared with original layered compound, nanosheet precipitate had good property under irradiation of ultraviolet light. [source] Morphologies-Controlled Synthesis and Optical Properties of Bismuth Tungstate Nanocrystals by a Low-Temperature Molten Salt MethodJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2006Lijin Xie Well-crystallized bismuth tungstate (Bi2WO6) powders with different morphologies were successfully synthesized via a low-temperature molten salt method. The powders were characterized by X-ray diffraction, transmission electron microscopy, and UV-Vis, respectively. It was found that the variation of morphology of the obtained Bi2WO6 powder mainly depends on the different reaction temperatures and the weight ratio of LiNO3,NaNO3 salt to precursor. In addition, the UV-Visible absorption spectra showed that the synthesized powders had strong light absorption properties not only in the ultraviolet light but also in the visible light region. [source] Method for checking label accuracy in barn and free range eggsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2005Neville G Gregory Abstract The aim was to develop a method for testing whether eggs sold as either ,barn' or free range' were laid under cage conditions. The surface patterns on 11 520 eggs from cage, barn and free range production systems were examined under ultraviolet light for distinctive fluorescent marks associated with each production system. In addition, the effects of egg washing, egg size, condensation and cage dusting on the prevalence of the fluorescent patterns associated with the cage production system were examined. The prevalence of fluorescent white double parallel lines with 2.2,2.5 cm spacing was a distinguishing feature for eggs laid on wire floors in cages. If five or more eggs in a sample of 90 eggs have double fluorescent lines it can be concluded with greater than 999 in 1000 probability that the batch contains some cage-laid eggs. Dust from the egg collection area below the feed trough was the main source of the fluorescent material. Washing the eggs removed or obscured the double lines. Egg size and condensation had limited effects on the prevalence of double lines. Infrequent dusting of the wire floor did not reduce the value of the test. Copyright © 2005 Society of Chemical Industry [source] Photostabilizing effect of some thermal stabilizers for poly(vinyl chloride) in the presence of fillerJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 4 2009D. Braun The commercial stabilizers Ca-Zn stearate and dibutyltin- S,S,-di(isooctyl thioglycolate) have been investigated as photostabilizers for rigid poly(vinyl chloride) (PVC) in the presence of two types of CaCO3 as filler (natural and modified). The results reveal the costabilizing efficiency of CaCO3, especially the natural type, when it is used in concentrations of 1,30% by weight. The stabilizing efficiency of CaCO3 is indicated by the longer induction period and the lower rate of dehydrochlorination. The stabilizing effect of CaCO3 may be attributed because of its opacity and action as a screening agent by reflecting ultraviolet light, thereby hindering the penetration of the light into the polymer matrix. In addition, CaCO3 has the ability to absorb the HCl evolved during processing. The slight difference in the stabilizing effect of natural CaCO3 compared to that of the modified one can be attributed to the modification process, that may decrease the number of active sites on the surface of CaCO3, that in turn are responsible for the absorption of the evolved HCl. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers [source] Ultraviolet photofragmentation of biomolecular ionsMASS SPECTROMETRY REVIEWS, Issue 3 2009James P. Reilly Abstract Mass spectrometric identification of all types of molecules relies on the observation and interpretation of ion fragmentation patterns. Peptides, proteins, carbohydrates, and nucleic acids that are often found as components of complex biological samples represent particularly important challenges. The most common strategies for fragmenting biomolecular ions include low- and high-energy collisional activation, post-source decay, and electron capture or transfer dissociation. Each of these methods has its own idiosyncrasies and advantages but encounters problems with some types of samples. Novel fragmentation methods that can offer improvements are always desirable. One approach that has been under study for years but is not yet incorporated into a commercial instrument is ultraviolet photofragmentation. This review discusses experimental results on various biological molecules that have been generated by several research groups using different light wavelengths and mass analyzers. Work involving short-wavelength vacuum ultraviolet light is particularly emphasized. The characteristics of photofragmentation are examined and its advantages summarized. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 28:425,447, 2009 [source] Novel initiation genes in squamous cell carcinomagenesis: A role for substrate-specific ubiquitylation in the control of cell survivalMOLECULAR CARCINOGENESIS, Issue 8 2007Amador Albor Abstract The study of experimental epidermal carcinogenesis offers several advantages over other epithelial carcinogenesis models, including easy accessibility and a database of research findings spanning over a century. Our studies make use of a clonal in vitro/in vivo keratinocyte carcinogenesis model with low frequency of ras mutation and derivative clonal-initiated lineages with distinct tumor fate. Analysis of this model has yielded candidate genes involved in the stages of initiation and tumorigenic progression, and has revealed novel roles for ubiquitylation in transcriptional control of survival and apoptotic pathways during the early stages of carcinogenesis. The expression of a recently described E3-ubiquitin ligase, Trim32, is elevated during initiation, and ectopic expression of Trim32 confers extended survival in response to terminal differentiation and ultraviolet light (UV) B/TNF-, death signals. Trim32 binds and ubiquitylates Piasy, controlling its stability and accumulation. Piasy is a SUMOylation factor involved in the control of apoptosis, senescence, and NF-,B activation. NF-,B is a survival factor for keratinocytes in response to UV irradiation, the main carcinogenic stimulus for the epidermis. Piasy inhibits NF-,B activity, and promotes keratinocyte apoptosis in response to UV and TNF-,. In human skin squamous cell carcinoma (SCC) samples, we found an inverse correlation between Trim32 and Piasy expression supporting a role for Trim32,Piasy interaction in human epidermal carcinogenesis. Our hypothesis is that increased expression of Trim32 may enhance epidermal carcinogenesis, by increasing the threshold of NF-,B activity through Piasy downmodulation. © 2007 Wiley-Liss, Inc. [source] Nanodisks protect amphotericin B from ultraviolet light and oxidation-induced damagePEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 6 2009Megan L Tufteland Abstract BACKGROUND: Macrolide polyene antibiotics possess potent broad-spectrum antifungal properties. Use of these agents in the field or in controlled environments is impeded by their poor water solubility and susceptibility to oxidation- and/or light-induced degradation. While typically used for human disease therapy, there is potential to expand the utility of polyene macrolide antibiotics, such as amphotericin B, for control of fungal disease infestation in agricultural settings. Thus, the susceptibility of this antibiotic to exposure-induced activity loss was evaluated. RESULTS: Incubation of the prototype polyene amphotericin B (AMB) with phospholipid vesicles and apolipoprotein A-I results in the formation of nanoscale complexes, termed nanodisks (NDs), capable of solubilizing significant quantities of AMB. To evaluate whether AMB incorporation into NDs conferred protection against light- or oxidation-induced damage, yeast growth inhibition assays were conducted. Compared with AMB solubilized in detergent micelles, AMB incorporated into NDs was protected from damage caused by exposure to UV light as well as by KMnO4 -induced oxidation. Furthermore, AMB-NDs inhibited growth of the turfgrass fungus Marasmius oreades Fr. CONCLUSION: Results suggest that this water-soluble formulation of a natural, biodegradable, antifungal agent represents a potential cost-effective, non-toxic and environmentally friendly substitute for chemical agents currently employed to control a range of fungal infestations. Copyright © 2009 Society of Chemical Industry [source] Photophysical Properties of Terbium Molecular-based Hybrids Assembled with Novel Ureasil LinkagesPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2007Bing Yan Three silica-based organic,inorganic hybrid systems composed of hydroxyl aromatic derivatives (2-acetylphenol [HAP], 2-hydroxy-3-methylbenzoic acid [HMBA], 3-hydroxy-meta-phthalic acid [HMPHTH] complexes) were prepared via a sol,gel process. The active hydroxyl groups of the three ligands grafted by 3-(triethoxysilyl)-propyl isocyanate (TESPIC) through hydrogen transfer addition reaction were used as multi-functional bridge components, which can coordinate to Tb3+ with carbonyl groups, strongly absorb ultraviolet light and effectively transfer energy to Tb3+ through their triplet excited state, as well as undergo polymerization or crosslinking reactions with tetraethoxysilane (TEOS), for anchoring terbium ions to silica backbone. NMR, FT-IR, UV,vis absorption, luminescence spectroscopy was used to investigate the obtained hybrid material. UV excitation in the organic component resulted in strong green emission from Tb3+ ions due to an efficient ligand-to-metal energy transfer mechanism. [source] | |||||||||||||||||||||||||||||||